Advertise virtually anything here, with CPM banner ads, CPM email ads and CPC contextual links. You can target relevant areas of the site and show ads based on geographical location of the user if you wish.

That's great to know! I actually found out that my site is currently targeted (which I wasn't aware of), though it seems to be just a small advertiser (not many impressions, but still a little extra income).

One advantage is these ads are pay-per-impression, even there is no click but still google ( and publisher ) get fixed amount of money for number of impressions.

This is a good options for low CTR sites.

Even though I am not getting good return on such ads compared to my regular ads, still I will keep this to re-assure google that mine is not a spam site and my contents are liked by humans also (not only robots)

In all honesty, the ones I get totally suck and I'd prefer to have the ability to turn them off. I don't even think that they're within the right context and targeting the right demographic that are my readers. Better to have one of my affiliate product ads showing than one of those babies.

Your mileage may vary, of course, but according to these stats, even at 1000 impressions, sometimes those site targeted ads don't even match up to my lowest playing context ad click.

They pay ridiculous high CPM. If you know your CTR is normally low, CPM ads can be a blessing in terms of getting you revenue for no clicks. And the visitor stays on your site able to click your other exit channels.